The present invention relates to the art of electric arc welding with a welder having a power supply of the switching type and more particularly to an electric arc welder of this type combined with a novel and unique controller to design the waveform.
Electric arc welding involves the movement of an electrode toward a workpiece while current is passed through the electrode and across an arc between the electrode and workpiece. Although some electric arc welders utilize a non-consumable electrode, most of the mass production arc welding involves an electrode which is consumed during the welding process whereby the electrode is melted by the arc and deposited on the workpiece. Thus, an arc welding process includes variable process characteristics, such as wire speed or electrode speed, gas composition, electrode diameter and workpiece metal. The actual electrical arc welding process at the production site takes into consideration these characteristics and involves a non-linear complex control system which determines the applicable metal transfer mode and the electrical parameters of the power supply performing the welding process. In order to achieve desirable results, a waveform is selected having several control parameters, which waveform is customized for the exact condition of each welding application. Thus, controlling arc welding has become an art which demands substantial knowledge and experience to select a waveform having several control parameters to produce an optimum welding process. A large number of controllers have been developed for use with electric arc welders that have real time current waveforms developed by welding engineers to optimize the welding process performed in the field. To accomplish this objective, a microprocessor based controller has been developed and is now used that allows an operator in the field to select one of many welding waveforms by merely using one of several overlays. This successful microprocessor based controller is illustrated in Blankenship U.S. Pat. No. 5,278,390 that is incorporated by reference herein. By using a known template for the controller, an operator selects a welding waveform having the desired control parameters especially developed for the selected weld process by a skilled welding engineer. This successful controller had a certain amount of adjustability in the field; however, such on-site adjustments were limited. Mass production use of arc welders has created a demand for the ability to conveniently adjust certain control parameters of the welding waveform in the field, especially when the welding process conditions are different than what is used in designing standard waveforms shipped with the welders (such as cable length, shielding gas and welding wire). Thus, there was a need for a controller to be used with an electric arc welder, where the controller can process a desired waveform that is adjusted interactively at the manufacturing site so the waveform is optimized for welding conditions and welding requirements for the job.
To fill this need, an electric arc welder was developed with a microprocessor based controller for the specific arc welder. This welder is shown in Hsu U.S. Pat. No. 6,002,104 incorporated by reference herein. The welder has a switching type power supply for creating a welding cycle, with a real time current waveform constituting several control parameters by rapidly switching a D.C. current in a controlled fashion by a pulse width modulator and it will be described with respect to such switching type power supply. This prior patented controller was used with various switching type power supplies normally used in electric arc welders; however, the Hsu patent shows a down chopper power supply for simplicity. In practice, an inverter type power supply having a waveform controlled by a pulse width modulator was controlled in accordance with the present invention. The microprocessor based controller included means for displaying a waveform generated on an electrically operated waveform screen, such as a CRT. In this manner, the operator at the production site viewed the actual waveform to be processed by the electric arc welder under the direction of the patented controller. Interactive means were employed for manually adjusting at least a portion of the waveform displayed on the waveform screen to generate a new waveform operating on the waveform screen and having the desired control parameters. Consequently, a prebuilt waveform was first displayed on the CRT, normally in a graph exhibiting current versus time. To change one of the control parameters, such as background current, peak current, current ramp, etc., a manual adjustment of the prebuilt waveform was performed manually and interactively on the waveform screen. In this manner, a new current waveform was exhibited on the waveform CRT screen. In accordance with somewhat standard practice, before the patented arc welder the pulse width modulator of the power supply was controlled in accordance with the newly created current waveform to cause the power supply itself to generate a welding cycle with the real time waveform corresponding to the new waveform on the waveform screen. The welder power supply executed the new control parameters exhibited as control parameters in the new waveform. In this manner, a desired waveform was exhibited and used by the electric arc welder. If there was a need to change a control parameter of the exhibited waveform, the waveform itself was modified visually by the operator on site and then employed for control of the electric arc welder. This interactive changing of the waveform, as it was visually displayed on a waveform screen, was novel to the welding field and was implemented by including a JAVA virtual machine with a welder control application program or an applet running within a browser in JAVA language. The JAVA control program was dedicated to the specific electric arc welder combined with the controller. Thus, the consumer product was an electric arc welder having a power supply with a microprocessor based controller that was driven by a program in JAVA language. This concept was accomplished by using a JAVA virtual machine as part of the on site controller. This new electric arc welding was interactively manipulated to create a waveform for controlling the actual real time waveform of the welding process. The controller performed its functions through real time adjustment of the pulse width modulator used in the switching power supply driving the welder.
In a welder using the patented technology of Hsu U.S. Pat. No. 6,002,104 the welder has a microprocessor with a JAVA virtual machine and controlled by at least one control application program in JAVA language. The program was dedicated to the particular welder being controlled. The microprocessor system included hardware with a first interface for an interactive display screen and a second interface for a manual data entry device, such as mouse or keyboard, that was used interactively to change the waveform on the display screen preparatory to the waveform being implemented on a digital communication link (such as ethernet or infrared) for outputting control parameters to the welder. The same communication channel was used to input operating parameters from the welder. In this manner, the electric welder was controlled by manual manipulation of the actual waveform to be used in the welding process preparatory to implementation of the welding process. As changes are required, certain control parameters were adjusted on the display screen to merely change the shape of the waveform being displayed. When the operating parameters from the welder were inputted to the microprocessor of the controller, a separate xe2x80x9cscopexe2x80x9d application program in JAVA language was selected and implemented by the controller. In this manner, the CRT of the controller was converted from a waveform editor to an oscilloscope display for reading parameters from the welder and for displaying these parameters as a soft oscilloscope on the face of the controller. The scope display used a window separate and distinct from the window used for editing the waveform. The screen of the controller was used to display either the waveform processed by the waveform editor application program or the oscilloscope plots processed by the scope application program. Both programs were processed by the JAVA virtual machine which was a part of the welder. The application programs were loaded into the virtual machine by a CD ROM that is loaded at the factory to program each of the welders preparatory to delivery. The physical media of distributing the JAVA object code or bytecode from the welding manufacturer to the customer used other forms, such as a floppy diskette, E-mail, web page and down loading by a modem. To change the operation program for the welders in the field, the patented welder periodically updated the control application program and/or the scope application program of the welders by a new CD ROM or by an Internet feed.
The patented controller of Hsu U.S. Pat. No. 6,002,104 displayed on its screen a waveform series of read out devices adjacent the waveform screen. A series of control parameters for the waveform were displayed adjacent the waveform screen, as read out values. The waveform was displayed on the waveform screen and contained a series of control parameters, some of which were recorded as read out values on the face of the controller adjacent the waveform screen. This total display is shown in FIG. 2 and is referred to as the graphic user interface or GUI. This display is used interactively to modify the waveform. The variable tables and waveform logic is provided by the memory stack as shown in FIG. 4. As an example of the display usage, the peak current of the waveform is displayed in an alpha numerical numbers on the face of the controller. As the waveform was modified interactively on the screen, the read but value was automatically changed accordingly. In addition, by adjusting one or more of the displayed control parameters at the read out device, the waveform itself was changed accordingly. The displayed control parameters, shown in the read out devices, had corresponding lock control parameter means for manually locking the display control parameters at preselected read out values. In this manner, the waveform was adjusted to change the value of a locked out control parameter. The prior art controller included a first override that was implemented to limit the value of one or more of the control parameters. In other words, if maximum current of the welder was at a set point, the control program processing a given waveform would prevent adjustment, either interactively or by a read out device, of the current to a level above the set maximum level. The same concept was used with a relational constraint wherein there is a fixed relationship of one control parameter to another control parameter. This fixed relationship was maintained. In this fashion, when one of the control parameters was adjusted, the other parameter is adjusted accordingly to maintain the set, fixed relationship. These are schemes utilized in the prior art patented welder to constrain the interactive manipulation of the waveform on the waveform screen or adjustment of the waveform through read out devices on the face of the controller. The JAVA virtual machine of the prior controller is provided with two or more application programs that are stand alone and can be selected by the operator who selects one or the other programs to be executed. The hardware of the controller includes a mouse or keyboard which latches onto certain points on the displayed waveform and allows the points to be moved or dragged in accordance with standard microprocessor operation. Consequently, there were graphically manipulating current waveforms for an arc welder in real time using JAVA technology. The welder monitors the actual waveform of the welder by analyzing operating parameters and using measurable electrical signals, such as arc current and voltage, derivative signals, such as impedance, power and energy, and process modes of operation. By using this concept, the operating signals or parameters from the welder itself were used to display and apply impedance of the arc and cable and instantaneous power of the arc and cable. Average current and voltage are sampled at a fixed rate and the welding time and the accumulated energy were also capable of being displayed in real time. If the optional scope program was employed, the output waveform created on the screen was analyzed and numerical data was displayed from various aspects of the displayed operating parameters. Other aspects of the actual operating condition of the welder were displayed and analyzed by using the scope program of the controller, not forming a part of the present invention.
In the prior art electric arc welder patented in Hsu U.S. Pat. No. 6,002,104, the processing logic was fixed and inflexible so that only certain types of waveforms pre-built into the program could be processed. For instance, a fixed wave shape template was selected for display and manipulation. See FIG. 3. The basic aspects of the template were fixed logic. Thus, the welder with a JAVA virtual machine could only select fixed templates for processing of specific current waveforms. There was no ability to select from a memory location certain data and display this as a waveform in a manner to change the behavior of the waveform template. In the prior art unit, the weld program compiled as object code or bytecodes was fixed to manipulate a fixed waveform logic of FIG. 4. If the waveform in FIG. 4 is changed, the JAVA source code must be changed to support the new waveform logic.
The present invention relates to the concept of creating a welding waveform script language used to specify waveform parameters exposed to the user as user variables for interaction with the graphic user interface shown in FIG. 2. A series of script language files written by script language presents waveforms graphically from a subset of parameters, constraints and display characteristics of the parameters. By using the script language or script files, the user variables and graphic constraints are directly processed by a graphic user interface (GUI) computer platform which in practice contains a JAVA virtual machine communicated with the operating system and hardware of the welder. By using the:script language, the relationship of the user variables are converted to data understood by the welder. Consequently, there is provided a user friendly programming digital welding system using script to draw any waveform as opposed to an operating program with pre-built waveforms. In accordance with one aspect of the invention, the welding waveform script file is compiled into a JAVA object code in the form of bytecodes. The JAVA bytecodes are processed in run time by the main operating JAVA program. When using the compiled script, the program is fixed; therefore, it is stable, general purpose and independent of the logic of each welding process.
In accordance with the invention, the welding waveform script language has a first section dedicated to user variables which are the parameters some of which are displayed on the read out portion of the CRT. The variable table for parameters are a subset of the fixed tables and logic of the stack in FIG. 4. This subset allows interaction on the graphic user interface of FIG. 2. The other portion of the welder waveform script language is the logic graphic construction which constructs the waveform on the graphic user interface to display the waveform for interactive manipulation by user as explained in Hsu U.S. Pat. No. 6,002,104. In each instance, the interactive manipulation as shown in Hsu U.S. Pat. No. 6,002,104, is processed in accordance with the present invention; however, this processing of welding process logic is separate from the main application and is driven by script language as opposed to fixed logic contained within the application.
By using script language, the interface with the operator allows adjustment of the waveform as well as the parameters in direct communication without the rigidity necessary in preprogrammed GUI designs.
In accordance with the present invention, an electric arc welder for creating a welding cycle with a real time current waveform constituting several parameters by switching a power supply in a controlled fashion under the control of a signal so the output of the power supply traces a desired form and dynamic reaction behavior to arc conditions defined by the control parameters. The switching of the power supply is by a pulse width modulator. This welder has a microprocessor controller for creating the signal and for reading the parameters. An operating computer system controlled by input from a dedicated computer program is combined with a system with a first interface for an interactive display for displaying the desired waveform and at least one manipulative control parameter and a second interface for a manual data entry device to change the waveform and/or the parameters. A digital communication link (such as ethernet or infrared) from the system causes the welder to perform the desired waveform by controlling the waveform controlling signal. There is provided a number of script language files each of which defines a given type of waveform and containing user manipulative variable table of control parameters and a graphic construction program to display a waveform to be manipulated by the welder. The script language file constitutes the primary aspect of the present invention. The welder has an input stage for directing a selected one of the script files to the GUI computer for operating the welder the various script language files. These files are individually processed for direct interactive communication with the operator of the welder to change the parameters and waveform before the waveform is used by the welder.
In accordance with another aspect of the present invention, the GUI computer contains a JAVA virtual machine and the input stage is either a compiler for converting the selected file to JAVA bytecodes or a script interpreter for directly processing the script file in run time. In accordance with another aspect of the present invention, both the interpreter and compiler is used for processing script language.
In accordance with another aspect of the present invention there is provided a method for controlling an electric arc welder for creating a welding cycle with a real time current waveform constituting several control parameters by switching power supply in a control fashion under the control of a signal so the output of the power supply traces a desired waveform and/or dynamic reaction behavior dictated by arc conditions defined by the control parameters. This welder has a microprocessor controller for creating the signal and for reading of the parameters. The method comprises providing a graphic user interface (GUI) program controlled by input from a GUI computer, providing a system with a first interface for an interactive display to display the desired waveform and at least one manipulative control parameter, a second interface for a manual data entry device to change the waveform and/or one of the parameters and a digital communication link for causing the welder to perform the desired waveform by controlling the signal, providing a number of script language files each defining a given type of waveform logic and containing a user manipulative variable table for control parameters and/or a graphic descriptive language to display a waveform to be implemented by the welder processing at least one of the script files to the GUI computer for operating the welder. The script files are converted into GUI components (read out, dynamic charts, panels to be loaded into a GUI program). The computer preferably contains a JAVA virtual machine which receives the data from the script language files either as compiled bytecodes or as interpreted text file.
In accordance with another aspect of the present invention, there is provided an electric arc welder for creating a welding cycle with a real time current waveform constituting several control parameters by switching a power supply in a controlled fashion under control of a signal, such as by a pulse width modulator, so the output of the power supply traces a desired waveform and dynamic reaction behavior to arc conditions in accordance with variables and waveform logic. The welder has a microprocessor controller with a computer operating program for creating the waveform control signals and reading at least some of said parameters. A number of script language files each defining a given waveform and containing a variable table and waveform logic in script language are compiled to convert the variable table to data structure native to the computer program and the waveform logic into native code of the computer program and a stage to use the variable table code and the waveform logic code to operate the power supply of the welder.
In the broadest sense, the power supply is a microprocessor controlled power supply for arc welding. In practice, it is a switching power supply controlled by a pulse width modulator under control of a signal from the microprocessor controller. The type of controller is not determinative of the invention.
In accordance with another aspect of the present invention, there is provided a novel graphic user interface for controlling and/or monitoring a welding process. The interface comprises at least one graphical widget defined by a scripting file loaded in run-time. The widget can be a slider, a text box, a switch, a choice, an intermediate chart, a button, a panel and combinations thereof.
The primary object of the present invention is the provision of a controller for an electric arc, which controller allows manipulation of a waveform on a screen for the purpose of changing the waveform to be used to determine operation of the welder wherein the waveform design and manipulation of behavior specified by scripting language file. Such control is preferably implemented by a JAVA virtual machine.
Another object of the present invention is the provision of a controller, as defined above, which controller can read the operating parameters of the welder to display the waveform and various operating parameters and allowing simplified operator manipulation of the display parameters and the waveform.
Still a further object of the present invention is the provision of an arc welder, as defined above, which welder incorporates a virtual machine as a stand alone application or as an applet within a browser used in the controller.
Still another object of the present invention is the provision of a method of operating an electric arc welder utilizing the scripting language for interaction by the operator and the controller to process displayed waveforms and displayed parameters.
Another object of the present invention is the provision of an electric arc welder and method, as defined above, which welder and method has the capability of modifying the logic of the waveform to construct the desired waveform without the constraints in the prior art, as shown in Hsu U.S. Pat. No. 6,002,104.
Yet a further object of this invention is a welder and method as defined above, which welder and method uses a scripting language program to both control a graphical user interface for interactive use and a load variable parameter table and waveform logic directly into the control program associated with the welder.
These and other objects and advantages will become apparent from the following description taken together with the accompanying drawings.